There are important public health concerns related to inappropriate use of venous thromboembolism (VTE) prophylaxis among medically ill hospitalized elderly patients with low risk of VTE occurrence. Specifically, use of anticoagulants (heparin products) for VTE prophylaxis when not medically indicated may be harmful, and is a major patient safety issue that also has a significant cost effect on health systems. To this end, the American College of Chest Physician (ACCP) 9th Edition guidelines explicitly recommend a risk-stratification approach, rather than universal use of anticoagulants for VTE prophylaxis. Even though many medical inpatients are at high risk for VTE, there are others whom do not have sufficient risk to warrant prophylaxis, and use in this population is inappropriate. The first aim of this application proposes to determine the magnitude and scope of inappropriate use of anticoagulant VTE prophylaxis in low risk older adults. This aim will be achieved by using data abstraction from the Duke University Health System electronic records to determine (1) the prevalence of low risk elders using criteria proposed by ACCP guidelines, and (2) anticoagulant VTE prophylaxis use in this group. Guideline directed use of pharmacologic VTE prophylaxis also emphasizes mobility evaluation. Mobility is a key component of risk stratification. Poor mobility evaluation by providers may be a significant barrier to appropriate use of VTE prophylaxis. Our second aim proposes to determine whether level of mobility during hospitalization is being used to influence use and duration of VTE prophylaxis among medically ill hospitalized elders. To achieve this aim, we will collect prospective observational data to objectively measure inpatient mobility using patient mounted accelerometers during patient hospital stays. Our goal is to improve the appropriateness of use of VTE prophylaxis among those in which the risks of harm may outweigh the benefit. Results from our study will provide important insights about use of risk assessment, and the relationship between patient mobility and VTE prophylaxis. These results are critical to understanding how to take the next steps toward improving the appropriate use and safety of anticoagulants in hospitalized older adults. Information from this study could be used in future proposals to study interventions to ultimately improve hospital practice in the care of older adults. Our investigative team at Duke is unique since we have expertise in all key fields of study: geriatrics, hospital medicine, hematology, and physical activity, that also have a longstanding history of working well with each other. As such, this collaborative team and research plan is designed to provide the principal investigator with a foundation from which to pursue an independent career in geriatric and hospital medicine research.